I'm new in Scrum and I have some doubts about the contracts used during a scrum project. There are some king of acceptance contract in each sprints or just one contract for all the project? And what kind of contracts do you ussualy use?
The Scrum Framework doesn't prescribe a contract model and it's fair to say that either fixed price or time & materials can be used...although it is certainly better to have an agile contract in place that provides for incremental funding. This is a big topic. I wrote an article on this subject a while back which you can use as a starting point: